Nonisolated PV Grid-Connected Inverter with a Minimum Boost Unit

PV grid-connected inverters (PGCIs) should shut down since the input voltage is smaller than the maximum grid voltage under shading condition (SC). A boost-type converter should be inserted between the PV array and the PGCI, so it increases the cost of the PGCI and reduce the efficiency of the PGCI. Therefore, a nonisolated PGCI with a minimum boost unit is proposed, which consists of a minimum boost unit and a full-bridge inverter. The minimum boost unit does not operate under normal condition (NM), while it only operates under SC. Its output voltage is the deviation between the output and input voltage of the inverter under SC, so it processes minimum power under SC. The working principle of the inverter is demonstrated. Finally, its theoretical analysis is proved by simulation results.